Even when AMDGPU support for SI/CIK has been enabled by the kernel, the [[radeon]] driver may be used instead of the AMDGPU driver.

Even when AMDGPU support for SI/CIK has been enabled by the kernel, the [[radeon]] driver may be used instead of the AMDGPU driver.

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One needs to set the {{ic|amdgpu}} as first to load in the [[Mkinitcpio#MODULES]] array, e.g. {{ic|1=MODULES=(amdgpu radeon)}}.

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To make sure the {{ic|amdgpu}} is loaded first use the following [[Mkinitcpio#MODULES]] array, e.g. {{ic|1=MODULES=(amdgpu radeon)}}.

==== Set required module parameters ====

==== Set required module parameters ====

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To enable full support for SI/CIK when using the {{ic|amdgpu}}, one needs to set [[kernel parameters]] to prevent the {{ic|radeon}} module from being loaded [http://www.phoronix.com/scan.php?page=article&item=linux-413-gcn101&num=1]:

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To enable full support for SI/CIK when using the {{ic|amdgpu}}, set the following [[kernel parameters]] to prevent the {{ic|radeon}} module from being used [http://www.phoronix.com/scan.php?page=article&item=linux-413-gcn101&num=1]:

Enable Southern Islands (SI) and Sea Islands (CIK) support

The linux package enables AMDGPU support for cards of the Southern Islands (SI) and Sea Islands (CIK). When building or compiling a kernel, CONFIG_DRM_AMDGPU_SI=Y and/or CONFIG_DRM_AMDGPU_CIK=Y should be be set in the config.

Even when AMDGPU support for SI/CIK has been enabled by the kernel, the radeon driver may be used instead of the AMDGPU driver.

To make sure the amdgpu is loaded first use the following Mkinitcpio#MODULES array, e.g. MODULES=(amdgpu radeon).

Set required module parameters

To enable full support for SI/CIK when using the amdgpu, set the following kernel parameters to prevent the radeon module from being used [1]:

AMD DC

AMD DC (display code), introduced in linux 4.15-4.17, is a new display stack that brings support for atomic mode-setting and HDMI/DP audio.
For more info about AMDGPU-DC, see this article.

If you are on GCN 1.1 or newer with AMDGPU and want to use DC, one needs to set amdgpu.dc=1 as kernel parameter.

AMDGPU PRO

Warning: Arch Linux is officially not supported.

Note:

To use the proprietary OpenCL component without AMDGPU PRO, installopencl-amdAUR instead.

A downgrade of the linux (4.9) and Xorg (1.18) packages is required to use AMDGPU PRO 17.10.

AMD provides a proprietary, binary userland driver called AMDGPU PRO, which works on top of the open-source AMDGPU kernel driver. The driver provides OpenGL, OpenCL, Vulkan and VDPAU support (although this is also supported by the open-source driver). For some workloads it provides better performance than the open-source driver (example benchmark), while for others it is true the contrary (example benchmark).

Enable early KMS

Kernel mode setting (KMS) is supported by the amdgpu driver and is mandatory and enabled by default.

KMS is typically initialized after the initramfs stage. It is possible, however, to enable KMS during the initramfs stage. To do this, add the amdgpu module to the MODULES line in /etc/mkinitcpio.conf:

MODULES=(amdgpu radeon)

Now, regenerate the initramfs:

# mkinitcpio -p linux

The change takes effect at the next reboot.

Xorg configuration

Xorg will automatically load the driver and it will use your monitor's EDID to set the native resolution. Configuration is only required for tuning the driver.

If you want manual configuration, create /etc/X11/xorg.conf.d/20-amdgpu.conf, and add the following:

/etc/X11/xorg.conf.d/20-amdgpu.conf

Section "Device"
Identifier "AMD"
Driver "amdgpu"
EndSection

Using this section, you can enable features and tweak the driver settings.

Performance tuning

Enabling video acceleration

Driver options

DRI sets the maximum level of DRI to enable. Valid values are 2 for DRI2 or 3 for DRI3. The default is 3 for DRI3 if the Xorg version is >= 1.18.3, otherwise DRI2 is used:

Option "DRI" "3"

TearFree controls tearing prevention using the hardware page flipping mechanism. If this option is set, the default value of the property is set to auto, which means that TearFree is on for outputs with rotation or other RandR transforms:

Setting the screen's depth under Xorg to 16 or 32 will cause problems/crash. To avoid that, you should use a standard screen depth of 24 by adding this to your "screen" section (assuming you have one; if you don't, add this to /etc/X11/xorg.conf.d/10-screen.conf).